Hi, congrats on reaching over 200 subscribers. Just a couple of ideas. First - your second episode talking about tectonics and mountain formation covered everything but why do the Rocky Mountains in North America exist? No tectonic plate boundries close and overall they really don't look like hot spots (with a wave to Yellowstone.) Second. You might do an episode on missing fantasy maps. Strip maps or real medieval maps. Rarely seen in fantasy settings. Keep up the good work. Have a nice day.
Thanks very much! It’s all very exciting.
The Rocky Mountains (with the exception of Yellowstone, which is indeed a hot spot) are actually a bit of a geological enigma! The period when they formed is called the Laramide Orogeny; the Laramide peaked about 60 million years ago, but we don’t know exactly when it began or ended. Most of the Rockies consist of very old rocks that have been uplifted, not new rocks that have been extruded from magma; if they were pushed up by magma, then it’s buried deep underneath the mountain. This leads to three main theories:
1. They were formed as continent-continent collision mountains when the modern west coast (mostly consisting of continent-ocean subduction arcs) came in.
2. They were formed by a continent-ocean boundary where the oceanic plate was subducted at a much shallower angle than normal, creating a mountain range a long way from the oceanic plate.
3. After the subducting plate in #2 broke off, its space was replaced by a rush of hot magma. This extended the width of the Basin & Range Province, which in turn pushed the Rockies and the Sierra Nevada upwards.
The three theories aren’t mutually exclusive – it could be two of them or all three.
As for the rest; I keep writing sections about mediaeval T-O maps and then cutting them out of the script for time, which is a shame because they’re quite bizarre. I haven’t heard of “strip maps” – Google just throws up maps of the Las Vegas Strip (to be fair I’ve been playing a lot of Fallout New Vegas lately), and Wikipedia redirects me to the page about street maps. Is that just a local term for street maps where you live?
